* sparc/arcfour-crypt.asm: Special unrolled code if SRC and DST

have compatible alignment. Improves performance by 20%, but I'm
not sure it's worth the extra complexity.

Rev: src/nettle/sparc/arcfour-crypt.asm:1.5

diff --git a/sparc/arcfour-crypt.asm b/sparc/arcfour-crypt.asm
index beadd91eb7fe67c1919e27c9a88bfe6b03e9232f..0dd9e363f18da388a733981b665779508566604b 100644 (file)
--- a/sparc/arcfour-crypt.asm
+++ b/sparc/arcfour-crypt.asm
@@ -18,7 +18,12 @@ C along with the nettle library; see the file COPYING.LIB.  If not, write to
 C the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 C MA 02111-1307, USA.
 
-C Registers
+C      Define to YES, to enable the complex code to special case SRC
+C      and DST with compatible alignment.
+       
+define(<WITH_ALIGN>, <NO>)
+
+C      Registers
 
 define(<CTX>,  <%i0>)
 define(<LENGTH>,<%i1>)
@@ -30,9 +35,103 @@ define(<J>, <%i5>)
 define(<SI>,   <%g1>)
 define(<SJ>,   <%g2>)
 define(<TMP>,  <%g3>)
+define(<N>,    <%o0>)
+define(<WORD>, <%o1>)
 
-C      FIXME: Consider using the callers window
+C      Encrypts n bytes, one byte at a time.
+C      ARCFOUR_BYTE_LOOP(n, label)
+define(<ARCFOUR_BYTE_LOOP>, <
+$2:    
+       add     I, 1, I
+       and     I, 0xff, I
+       ldub    [CTX + I], SI
+       subcc   $1,1,$1
+       ldub    [SRC], TMP
+       add     J, SI, J
+       and     J, 0xff, J
+       ldub    [CTX + J], SJ
+       add     SRC, 1, SRC
+       stb     SI, [CTX + J]
+       add     SI, SJ, SI
+       and     SI, 0xff, SI
+       ldub    [CTX + SI], SI
+       stb     SJ, [CTX + I]
+       xor     TMP, SI, TMP
+       stb     TMP, [DST]
+       bne     $2
+       add     DST, 1, DST
+>)dnl
+
+C      Encrypts 4n bytes, four at a time. Requires proper alignmentof
+C      SRC and DST.
+C      ARCFOUR_WORD_LOOP(n, label)
+define(<ARCFOUR_WORD_LOOP>, <
+$2:
+       add     I, 1, I
+       and     I, 0xff, I
+       ldub    [CTX + I], SI
+       ld      [SRC], WORD
+       add     J, SI, J
+       and     J, 0xff, J
+       ldub    [CTX + J], SJ
+       stb     SI, [CTX + J]
+       add     SI, SJ, SI
+       and     SI, 0xff, SI
+       ldub    [CTX + SI], TMP
+       stb     SJ, [CTX + I]
 
+       add     I, 1, I
+       and     I, 0xff, I
+       ldub    [CTX + I], SI
+       add     SRC, 4, SRC
+       add     J, SI, J
+       and     J, 0xff, J
+       ldub    [CTX + J], SJ
+       stb     SI, [CTX + J]
+       add     SI, SJ, SI
+       and     SI, 0xff, SI
+       ldub    [CTX + SI], SI
+       sll     TMP, 8, TMP
+       stb     SJ, [CTX + I]
+       or      TMP, SI, TMP
+       
+       add     I, 1, I
+       and     I, 0xff, I
+       ldub    [CTX + I], SI
+       subcc   $1, 1, $1
+       add     J, SI, J
+       and     J, 0xff, J
+       ldub    [CTX + J], SJ
+       stb     SI, [CTX + J]
+       add     SI, SJ, SI
+       and     SI, 0xff, SI
+       ldub    [CTX + SI], SI
+       sll     TMP, 8, TMP
+       stb     SJ, [CTX + I]
+       or      TMP, SI, TMP
+
+       add     I, 1, I
+       and     I, 0xff, I
+       ldub    [CTX + I], SI
+       C       empty slot
+       add     J, SI, J
+       and     J, 0xff, J
+       ldub    [CTX + J], SJ
+       stb     SI, [CTX + J]
+       add     SI, SJ, SI
+       and     SI, 0xff, SI
+       ldub    [CTX + SI], SI
+       sll     TMP, 8, TMP
+       stb     SJ, [CTX + I]
+       or      TMP, SI, TMP
+       xor     WORD, TMP, WORD
+       st      WORD, [DST]
+       
+       bne     $2
+       add     DST, 4, DST
+>)dnl
+               
+C      FIXME: Consider using the callers window
 define(<FRAME_SIZE>, 104)
 
        .file "arcfour-crypt.asm"
@@ -56,26 +155,44 @@ PROLOGUE(nettle_arcfour_crypt)
        and     I, 0xff, J
        srl     I, 8, I
 
-.Loop: 
-       add     I, 1, I
-       and     I, 0xff, I
-       ldub    [CTX + I], SI
-       subcc   LENGTH,1,LENGTH
-       ldub    [SRC], TMP
-       add     J, SI, J
-       and     J, 0xff, J
-       ldub    [CTX + J], SJ
-       add     SRC, 1, SRC
-       stb     SI, [CTX + J]
-       add     SI, SJ, SI
-       and     SI, 0xff, SI
-       ldub    [CTX + SI], SI
-       stb     SJ, [CTX + I]
-       xor     TMP, SI, TMP
-       stb     TMP, [DST]
-       bne     .Loop
-       add     DST, 1, DST
+ifelse(WITH_ALIGN, YES, <
+       C       Check if SRC and DST have compatible alignment
+       xor     SRC, DST, TMP
+       andcc   TMP, 3, TMP
+
+       bne     .Lrest
+       nop
+       
+       andcc   DST, 3, N
+       bz      .Laligned
+       nop
+       
+       sub     N, 4, N
+       neg     N
+       cmp     N, LENGTH
+       bgeu    .Lrest
+       nop
+       
+       sub     LENGTH, N, LENGTH
+       
+       ARCFOUR_BYTE_LOOP(N, .Lunalignedloop)
+
+.Laligned:
+       srl     LENGTH, 2, N
+       cmp     N, 0
+       be      .Lrest
+       nop
+       
+       ARCFOUR_WORD_LOOP(N, .Lalignedloop)
+
+       andcc   LENGTH, 3, LENGTH
+       bz      .Ldone
+       nop
+>)
+.Lrest:
+       ARCFOUR_BYTE_LOOP(LENGTH, .Loop)
 
+.Ldone:
        C       Save back I and J       
        sll     I, 8, I
        or      I, J, I
@@ -93,9 +210,11 @@ C 1:        nettle-1.13 C-code
 C 2:   First working version of the assembler code
 C 3:   Moved load of source byte
 C 4:   Better instruction scheduling
+C 5:   Special case SRC and DST with compatible alignment
 
 C      MB/s    cycles/byte     Code size (bytes)
 C 1:   6.6     12.4            132
 C 2:   5.6     14.5            116
 C 3:   6.0     13.5            116
 C 4:   6.5     12.4            116
+C 5:   7.9     10.4            496